Iron–sulfur cluster biosynthesis protein OsSUFD is essential for chloroplast function and environmental adaptation in rice

Ting Zou; Rui Wang; Shiyue Xing; Kun Peng; Yun Chen; Shanding Xu; Jiefeng Song; Xue Ding; Xuan Liang; Yongqin Deng; Zelin Peng; Menglian Feng; Ji Wang; Jinghua Jin; Shiquan Wang; Qiming Deng; Jun Zhu; Yueyang Liang; Ping Li; Shuangcheng Li

The Plant Journal, Vol. 126, Issue 2, Article number: e70886 (2026), April 2026 (IF=5.7).

Abstract

Iron–sulfur (Fe–S) clusters are essential cofactors for diverse biological processes, and their biosynthesis in chloroplasts is mediated by the evolutionarily conserved sulfur utilization factor (SUF) pathway. Here, we report that mutations in the rice homolog of bacterial and plant SUFD, designated OsSUFD, lead to defective chloroplast development and premature leaf senescence. Biochemical analyses show that OsSUFD presumably assembles with OsSUFB and OsSUFC to form a chloroplastic scaffold complex. Mutations in OsSUFD disrupt iron homeostasis and reduce the accumulation of plastidial Fe–S proteins. Furthermore, impaired OsSUFD function compromises rice tolerance to oxidative and heat stresses, accompanied by increased reactive oxygen species accumulation and decreased chlorophyll levels. Overexpression of OsSUFD enhances tolerance to these abiotic stresses. Collectively, our findings define the conserved architectural features of the rice SUF system and reveal its essential roles in Fe–S cluster biogenesis, chloroplast function maintenance, and environmental stress tolerance.

Keywords：chloroplast; environmental stress; Fe–S cluster; OsSUFD; rice; SUF system